Objective: To understand the influence of diabetes on the clinical and bacteriological aspects and treatment outcome of pulmonary tuberculosis (PTB) patients.
Setting and design: Records of 692 consecutive smear-positive PTB patients admitted to a referral hospital in Riyadh, Saudi Arabia, were reviewed retrospectively. The characteristics of 187 patients with diabetes mellitus (PTB-DM group) were compared to 505 patients without DM (PTB group).
Results: In the PTB-DM group, 65.2% of the patients had numerous acid-fast bacilli (AFB) on sputum smear examination compared to 54.1% in the control group (P = 0.008). Among new cases, PTB-DM patients had a lower prevalence of resistance to any anti-tuberculosis drug (6.4% vs. 16.0%, P = 0.007) and achieved higher sputum conversion rates at the end of 3 months of treatment (98.9% vs. 94.7%, P = 0.013). Favourable outcomes (cured/treatment completed), failure, death and default were comparable in both groups (P = 0.7005).
Conclusions: PTB-DM patients have a higher pre-treatment bacillary load, a lower prevalence of anti-tuberculosis drug resistance and achieve slightly higher sputum conversion by the end of 3 months of treatment compared to non-diabetic patients. The association of diabetes does not alter the final treatment outcome among PTB patients.